| Summary: | The enhanced dielectric permittivity (ε′) while retaining a low loss tangent (tanδ) in silver nanoparticle−(In<sub>1/2</sub>Nb<sub>1/2</sub>)<sub>0.1</sub>Ti<sub>0.9</sub>O<sub>2</sub>/poly(vinylidene fluoride) (Ag-INTO/PVDF) composites with different volume fractions of a filler (<i>f</i><sub>Ag-INTO</sub>) was investigated. The hybrid particles were fabricated by coating Ag nanoparticles onto the surface of INTO particles, as confirmed by X-ray diffraction. The ε′ of the Ag−INTO/PVDF composites could be significantly enhanced to ~86 at 1 kHz with a low tanδ of ~0.044. The enhanced ε′ value was approximately >8-fold higher than that of the pure PVDF polymer for the composite with <i>f</i><sub>Ag-INTO</sub> = 0.5. Furthermore, ε′ was nearly independent of frequency in the range of 10<sup>2</sup>–10<sup>6</sup> Hz. Therefore, filling Ag−INTO hybrid particles into a PVDF matrix is an effective way to increase ε′ while retaining a low tanδ of polymer composites. The effective medium percolation theory model can be used to fit the experimental ε′ values with various <i>f</i><sub>Ag-INTO</sub> values. The greatly increased ε′ primarily originated from interfacial polarization at the conducting Ag nanoparticle–PVDF and Ag–INTO interfaces, and it was partially contributed by the high ε′ of INTO particles. A low tanδ was obtained because the formation of the conducting network in the polymer was inhibited by preventing the direct contact of Ag nanoparticles.
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